This invention is related to the field of organometal catalyst compositions.
The production of polymers is a multi-billion dollar business. This business produces billions of pounds of polymers each year. Millions of dollars have been spent on developing technologies that can add value to this business.
One of these technologies is called metallocene catalyst technology. Metallocene catalysts have been known since about 1958. However, their low productivity did not allow them to be commercialized. About 1974, it was discovered that contacting one part water with one part trimethylaluminum to form methyl aluminoxane, and then contacting such methyl aluminoxane with a metallocene compound, formed a metallocene catalyst that had greater activity. However, it was soon realized that large amounts of expensive methyl aluminoxane were needed to form an active metallocene catalyst. This has been a significant impediment to the commercialization of metallocene catalysts.
Fluoro organic borate compounds have been used in place of large amounts of methyl aluminoxane. However, this is not satisfactory, since these borate compounds are very sensitive to poisons and decomposition, and can also be very expensive.
It should also be noted that having a heterogeneous catalyst is important. This is because heterogeneous catalysts are required for most modern commercial polymerization processes. Furthermore, heterogeneous catalysts can lead to the formation of substantially uniform polymer particles that have a high bulk density. These types of substantially uniform particles are desirable because they improve the efficiency of polymer production and transportation. Efforts have been made to produce heterogeneous metallocene catalysts; however, these catalysts have not been entirely satisfactory.
An object of this invention is to provide a process that produces a catalyst composition that can be used to polymerize at least one monomer to produce a polymer.
Another object of this invention is to provide the catalyst composition.
Another object of this invention is to provide a process comprising contacting at least one monomer and the catalyst composition under polymerization conditions to produce the polymer.
These objects, and other objects, will become more apparent to those with ordinary skill in the art after reading this disclosure.
In accordance with one embodiment of this invention, a process to produce a catalyst composition is provided. The process comprises (or optionally, xe2x80x9cconsists essentially of,xe2x80x9d or xe2x80x9cconsists ofxe2x80x9d) contacting at least one organometal compound, at least one organoaluminum compound, and at least one solid to produce the catalyst composition,
wherein the organometal compound has the following general formula:
(X1)(X2)(X3)(X4)M1
wherein M1 is selected from the group consisting of titanium, zirconium, and hafnium;
wherein (X1) is independently selected from the group consisting of cyclopentadienyls, indenyls, fluorenyls, substituted cyclopentadienyls, substituted indenyls, and substituted fluorenyls;
wherein substituents on the substituted cyclopentadienyls, substituted indenyls, and substituted fluorenyls of (X1) are selected from the group consisting of aliphatic groups, cyclic groups, combinations of aliphatic and cyclic groups, silyl groups, alkyl halide groups, halides, organometallic groups, phosphorus groups, nitrogen groups, silicon, phosphorus, boron, germanium, and hydrogen;
wherein at least one substituent on (X1) can be a bridging group which connects (X1) and (X2);
wherein (X3) and (X4) are independently selected from the group consisting of halides, aliphatic groups, substituted aliphatic groups, cyclic groups, substituted cyclic groups, combinations of aliphatic groups and cyclic groups, combinations of substituted aliphatic groups and cyclic groups, combinations of aliphatic groups and substituted cyclic groups, combinations of substituted aliphatic groups and substituted cyclic groups, amido groups, substituted amido groups, phosphido groups, substituted phosphido groups, alkyloxide groups, substituted alkyloxide groups, aryloxide groups, substituted aryloxide groups, organometallic groups, and substituted organometallic groups;
wherein (X2) is selected from the group consisting of cyclopentadienyls, indenyls, fluorenyls, substituted cyclopentadienyls, substituted indenyls, substituted fluorenyls, halides, aliphatic groups, substituted aliphatic groups, cyclic groups, substituted cyclic groups, combinations of aliphatic groups and cyclic groups, combinations of substituted aliphatic groups and cyclic groups, combinations of aliphatic groups and substituted cyclic groups, combinations of substituted aliphatic groups and substituted cyclic groups, amido groups, substituted amido groups, phosphido groups, substituted phosphido groups, alkyloxide groups, substituted alkyloxide groups, aryloxide groups, substituted aryloxide groups, organometallic groups, and substituted organometallic groups;
wherein substituents on (X2) are selected from the group consisting of aliphatic groups, cyclic groups, combinations of aliphatic groups and cyclic groups, silyl groups, alkyl halide groups, halides, organometallic groups, phosphorus groups, nitrogen groups, silicon, phosphorus, boron, germanium, and hydrogen;
wherein at least one substituent on (X2) can be a bridging group which connects (X1) and (X2);
wherein the organoaluminum compound has the following general formula:
Al(X5)n(X6)3xe2x88x92n
wherein (X5) is a hydrocarbyl having from 1-20 carbon atoms;
wherein (X6) is a halide, hydride, or alkoxide;
wherein the solid is selected from the group consisting of titanium tetrafluoride, zirconium tetrafluoride, and a treated solid oxide compound;
wherein the treated solid oxide compound comprises a solid oxide compound having titanium tetrafluoride or zirconium tetrafluoride deposited on the surface of the solid oxide compound; and
wherein the solid oxide comprises oxygen and at least one element selected from the group consisting of groups 2-9 and 11-17 of the Periodic Table of Elements, including lanthanides and actinides.
In accordance with another embodiment of this invention, a process is provided comprising contacting at least one monomer and the catalyst composition under polymerization conditions to produce a polymer.
In accordance with another embodiment of this invention, an article is provided. The article comprises the polymer produced in accordance with this invention.
A process to produce a catalyst composition is provided. The process comprises contacting at least one organometal compound, at least one organoaluminum compound, and at least one solid.
Organometal compounds used in this invention have the following general formula:
(X1)(X2)(X3)(X4)M1
In this formula, M1 is selected from the group consisting of titanium, zirconium, and hafnium. Currently, it is most preferred when M1 is zirconium.
In this formula, (X1) is independently selected from the group consisting of (hereafter xe2x80x9cGroup OMC-Ixe2x80x9d) cyclopentadienyls, indenyls, fluorenyls, substituted cyclopentadienyls, substituted indenyls, such as, for example, tetrahydroindenyls, and substituted fluorenyls, such as, for example, octahydrofluorenyls.
Substituents on the substituted cyclopentadienyls, substituted indenyls, and substituted fluorenyls of (X1) can be selected independently from the group consisting of aliphatic groups, cyclic groups, combinations of aliphatic and cyclic groups, silyl groups, alkyl halide groups, halides, organometallic groups, phosphorus groups, nitrogen groups, silicon, phosphorus, boron, germanium, and hydrogen, as long as these groups do not to substantially, and adversely, affect the polymerization activity of the catalyst composition.
Suitable examples of aliphatic groups are hydrocarbyls, such as, for example, paraffins and olefins. Suitable examples of cyclic groups are cycloparaffins, cycloolefins, cycloacetylenes, and arenes. Substituted silyl groups include, but are not limited to, alkylsilyl groups where each alkyl group contains from 1 to about 12 carbon atoms, arylsilyl groups, and arylalkylsilyl groups. Suitable alkyl halide groups have alkyl groups with 1 to about 12 carbon atoms. Suitable organometallic groups include, but are not limited to, substituted silyl derivatives, substituted tin groups, substituted germanium groups, and substituted boron groups.
Suitable examples of such substituents are methyl, ethyl, propyl, butyl, tert-butyl, isobutyl, amyl, isoamyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, dodecyl, 2-ethylhexyl, pentenyl, butenyl, phenyl, chloro, bromo, iodo, trimethylsilyl, and phenyloctylsilyl.
In this formula, (X3) and (X4) are independently selected from the group consisting of (hereafter xe2x80x9cGroup OMC-IIxe2x80x9d) halides, aliphatic groups, substituted aliphatic groups, cyclic groups, substituted cyclic groups, combinations of aliphatic groups and cyclic groups, combinations of substituted aliphatic groups and cyclic groups, combinations of aliphatic groups and substituted cyclic groups, combinations of substituted aliphatic and substituted cyclic groups, amido groups, substituted amido groups, phosphido groups, substituted phosphido groups, alkyloxide groups, substituted alkyloxide groups, aryloxide groups, substituted aryloxide groups, organometallic groups, and substituted organometallic groups, as long as these groups do not substantially, and adversely, affect the polymerization activity of the catalyst composition.
Suitable examples of aliphatic groups are hydrocarbyls, such as, for example, paraffins and olefins. Suitable examples of cyclic groups are cycloparaffins, cycloolefins, cycloacetylenes, and arenes. Currently, it is preferred when (X3) and (X4) are selected from the group consisting of halides and hydrocarbyls, where such hydrocarbyls have from 1 to about 1 0 carbon atoms. However, it is most preferred when (X3) and (X4) are selected from the group consisting of fluoro, chloro, and methyl.
In this formula, (X2) can be selected from either Group OMC-I or Group OMC-II.
At least one substituent on (X1) or (X2) can be a bridging group that connects (X1) and (X2), as long as the bridging group does not substantially, and adversely, affect the activity of the catalyst composition. Suitable bridging groups include, but are not limited to, aliphatic groups, cyclic groups, combinations of aliphatic groups and cyclic groups, phosphorous groups, nitrogen groups, organometallic groups, silicon, phosphorus, boron, and germanium.
Suitable examples of aliphatic groups are hydrocarbyls, such as, for example, paraffins and olefins. Suitable examples of cyclic groups are cycloparaffins, cycloolefins, cycloacetylenes, and arenes. Suitable organometallic groups include, but are not limited to, substituted silyl derivatives, substituted tin groups, substituted germanium groups, and substituted boron groups.
Various processes are known to make these organometal compounds. See, for example, U.S. Pat. Nos. 4,939,217; 5,210,352; 5,436,305; 5,401,817; 5,631,335, 5,571,880; 5,191,132; 5,480,848; 5,399,636; 5,565,592; 5,347,026; 5,594,078; 5,498,581; 5,496,781; 5,563,284; 5,554,795; 5,420,320; 5,451,649; 5,541,272; 5,705,478; 5,631,203; 5,654,454; 5,705,579; and 5,668,230; the entire disclosures of which are hereby incorporated by reference.
Specific examples of such organometal compounds are as follows: 
Preferably, the organometal compound is selected from the group consisting of 
Organoaluminum compounds have the following general formula:
Al(X5)n(X6)3xe2x88x92n
In this formula, (X5) is a hydrocarbyl having from 1 to about 20 carbon atoms. Currently, it is preferred when (X5) is an alkyl having from 1 to about 10 carbon atoms. However, it is most preferred when (X5) is selected from the group consisting of methyl, ethyl, propyl, butyl, and isobutyl.
In this formula, (X6) is a halide, hydride, or alkoxide. Currently, it is preferred when (X6) is independently selected from the group consisting of fluoro and chloro. However, it is most preferred when (X6) is chloro.
In this formula, xe2x80x9cnxe2x80x9d is a number from 1 to 3 inclusive. However, it is preferred when xe2x80x9cnxe2x80x9d is 3.
Examples of such compounds are as follows:
trimethylaluminum;
triethylaluminum (TEA);
tripropylaluminum;
diethylaluminum ethoxide;
tributylaluminum;
diusobutylaluminum hydride;
triisobutylaluminum hydride;
triisobutylaluminum; and
diethylaluminum chloride.
Currently, TEA is preferred.
The treated solid oxide compound comprises a solid oxide compound having titanium tetrafluoride or zirconium tetrafluoride deposited on the surface of the solid oxide compound. Generally, any high surface area, high porosity, solid oxide compound can be used. The solid oxide compound comprises oxygen and at least one element selected from the group consisting of groups 2-9 and 11-17 of the Periodic Table of Elements, including lanthanides and actinides. However, it is preferred when the element is selected from the group consisting of Al, B, Be, Bi, Cd, Co, Cr, Cu, Fe, Ga, La, Mn, Mo, Ni, Sb, Si, Sn, Sr, Th, Ti, V, W, P, Y, Zn, and Zr. Preferably, the solid oxide compound is selected from the group consisting of alumina, silica, silica-alumina, aluminophosphate, aluminoborate, silica-zironia, silica-titania, thoria, and mixtures thereof. The solid oxide compound can be produced by any method known in the art, such as, for example, by gelling, co-gelling, impregnation of one compound onto another, and flame hydrolysis.
Generally, the specific surface area of the solid oxide compound is from about 100 to about 1000 m2/g, preferably, from about 200 to about 800 m2/g, and most preferably, from 250 to 600 m2/g after calcining at 500xc2x0 C.
The specific pore volume of the solid oxide compound is typically greater than about 0.5 cm3/g, preferably, greater than about 0.8 cm3/g, and most preferably, greater than 1.0 cm3/g.
Calcining is conducted at various steps in the production of the treated solid oxide compound. Generally, calcining of the solid oxide compound is conducted at a temperature in the range of about 200xc2x0 C. to about 900xc2x0 C., preferably in a range of about 300xc2x0 to about 700xc2x0 C., and most preferably in a range of 350xc2x0 C. to 600xc2x0 C. Typically, calcining is conducted for about 1 minute to about 100 hours, preferably for about 1 hour to about 50 hours, and most preferably, for 3 hours to 20 hours. Calcining is performed typically in an inert atmosphere. Alternatively, an oxidizing atmosphere, such as, for example, oxygen or air, or a reducing atmosphere, such as, for example, hydrogen or carbon monoxide, can be utilized.
When the treated solid oxide compound is utilized to produce the catalyst composition, the TiF4 or ZrF4 can be deposited on the solid oxide compound by any means known in the art. Generally, the TiF4 or ZrF4 can be deposited on the solid oxide compound by a process of impregnation, sublimation, or decomposition of a salt. For best results, the solid oxide compound contains between about 0.01 and about 10 millimoles of TiF4 or ZrF4 per gram of solid oxide compound before calcining or contained on a precalcined solid oxide compound, preferably between about 0.1 and about 5 millimoles, and most preferably between 0.5 and 3.0 millimoles.
When an impregnation process is utilized, the process comprises first calcining the solid oxide compound to remove moisture to produce a calcined solid oxide compound. Calcining was discussed previously in this disclosure. Secondly, TiF4 or ZrF4 is dissolved in any aprotic polar solvent, such as, for example, acetonitrile, carbon tetrachloride, dimethyl sulfoxide, ethylene glycol alkoxides, glymes, and mixtures thereof, to produce a metal fluoride solution. The metal fluoride solution then is contacted with the calcined solid oxide compound to produce a metal fluoride/solid oxide compound mixture. Then, the aprotic polar solvent is evaporated from the metal fluoride/solid oxide compound mixture leaving the TiF4 or ZrF4 deposited on the solid oxide compound, thereby, producing the treated solid oxide compound. Optionally, for best results, the treated solid oxide compound can be dried thoroughly, even calcined up to a temperature in a range of about 300xc2x0 C. to about 500xc2x0 C., to remove traces of the aprotic polar solvent.
When a sublimation process is utilized to produce the treated solid oxide compound, the process comprises depositing TiF4 onto the solid oxide compound by gas phase deposition. ZrF4 cannot be deposited by sublimation onto the solid oxide compound. In this process, TiF4, which sublimes at about 284xc2x0 C. at ambient pressure, is evaporated in the presence of the solid oxide compound and then condensed onto the solid oxide compound either through adsorption, or in some cases, through reaction with the solid oxide compound. Typically, the solid oxide compound is calcined to produce a calcined solid oxide compound. The calcined solid oxide compound is dry mixed with TiF4 to produce a TiF4/solid oxide compound mixture. The calcining of the solid oxide compound is conducted as discussed previously in this disclosure. This TiF4/solid oxide compound mixture then is calcined at a temperature in a range of about 250xc2x0 C. to about 600xc2x0 C., preferably 300xc2x0 C. to 500xc2x0 C. Generally, calcining time is in the range of about 1 minute to about 10 hours, preferably, 1 hour to 5 hours.
The process of depositing TiF4 or ZrF4 by decomposition of a salt comprises impregnating the solid oxide compound with a solution comprising ammonium hexafluorotitanate ((NH4)2TiF6) or ammonium hexafluorozirconate ((NH4)2ZrF6) and a solvent to produce an ammonium metal fluoride-containing solid oxide compound. The solvent is evaporated, and the ammonium metal fluoride-containing solid oxide compound is calcined at sufficiently high temperature to decompose the ammonium salt to TiF4 or ZrF4, thereby, releasing ammonium fluoride (NH4F) in the process to produce the treated solid oxide compound. In this embodiment, the solid oxide compound can be virgin or previously calcined as discussed previously in this disclosure. The solvent can be water or a polar organic solvent, such as, for example alcohol or acetone. The calcining of the ammonium metal fluoride-containing solid oxide compound is in a range of about 250xc2x0 C. to 600xc2x0 C., preferably 300xc2x0 C. to 550xc2x0 C. and over a time of one minute to 10 hours, preferably one to five hours.
The catalyst compositions of this invention can be produced by contacting the organometal compound, the organoaluminum compound, and the solid, together. This contacting can occur in a variety of ways, such as, for example, blending. Furthermore, each of these compounds can be fed into a reactor separately, or various combinations of these compounds can be contacted together before being further contacted in the reactor, or all three compounds can be contacted together before being introduced into the reactor.
Currently, one method is to first contact the organometal compound and the solid together, for about 1 minute to about 24 hours, preferably, 1 minute to 1 hour, at a temperature from about 10xc2x0 C. to about 200xc2x0 C., preferably 15xc2x0 C. to 80xc2x0 C., to form a first mixture, and then contact this first mixture with an organoaluminum compound to form the catalyst composition.
Another method is to precontact the organometal compound, the organoaluminum compound, and the solid before injection into a polymerization reactor for about 1 minute to about 24 hours, preferably, 1 minute to 1 hour, at a temperature from about 10xc2x0 C. to about 200xc2x0 C., preferably 20xc2x0 C. to 80xc2x0 C.
A weight ratio of the organoaluminum compound to the solid in the catalyst composition ranges from about 5:1 to about 1:1000, preferably, from about 3:1 to about 1:100, and most preferably, from 1:1 to 1:50.
A weight ratio of the solid to the organometal compound in the catalyst composition ranges from about 10,000:1 to about 1:1, preferably, from about 1000:1 to about 10:1, and most preferably, from 250:1 to 20:1. These ratios are based on the amount of the components combined to give the catalyst composition.
After contacting, the catalyst composition comprises a post-contacted organometal compound, a post-contacted organoaluminum compound, and a post-contacted solid. Preferably, the post-contacted solid is the majority, by weight, of the catalyst composition. Often times, specific components of a catalyst are not known, therefore, for this invention, the catalyst composition is described as comprising post-contacted compounds.
A weight ratio of the post-contacted organoaluminum compound to the post-contacted solid in the catalyst composition ranges from about 5:1 to about 1:1000, preferably, from about 3:1 to about 1:100, and most preferably, from 1:1 to 1:50.
A weight ratio of the post-contacted treated solid to the post-contacted organometal compound in the catalyst composition ranges from about 10,000:1 to about 1:1, preferably, from about 1000:1 to about 10:1, and most preferably, from 250:1 to 20:1. These ratios are based on the amount of the components combined to give the catalyst composition.
The activity of the catalyst composition of this invention is greater than about 50 grams of polymer per gram of solid per hour, more preferably greater than about 75, and most preferably greater than 100. This activity is measured under slurry polymerization conditions, using isobutane as the diluent, and with a polymerization temperature of 90xc2x0 C., and an ethylene pressure of 550 psig. The reactor should have substantially no indication of any wall scale, coating or other forms of fouling.
One of the important aspects of this invention is that no aluminoxane needs to be used in order to form the catalyst composition. Aluminoxane is an expensive compound that greatly increases polymer production costs. This also means that no water is needed to help form such aluminoxanes. This is beneficial because water can sometimes kill a polymerization process. Additionally, it should be noted that no fluoro organic borate compounds need to be used in order to form the catalyst composition. In summary, this means that the catalyst composition, which is heterogenous, and which can be used for polymerizing monomers, can be easily and inexpensively produced because of the substantial absence of any aluminoxane compounds or fluoro organic borate compounds. It should be noted that organochromium compounds and MgCl2 are not needed in order to form the catalyst composition. Although aluminoxane, fluoro organic borate compounds, organochromium compounds, or MgCl2 are not needed in the preferred embodiments, these compounds can be used in other embodiments of this invention.
In another embodiment of this invention, a process comprising contacting at least one monomer and the catalyst composition to produce a polymer is provided. The term xe2x80x9cpolymerxe2x80x9d as used in this disclosure includes homopolymers and copolymers. The catalyst composition can be used to polymerize at least one monomer to produce a homopolymer or a copolymer. Usually, homopolymers are comprised of monomer residues, having 2 to about 20 carbon atoms per molecule, preferably 2 to about 10 carbon atoms per molecule. Currently, it is preferred when at least one monomer is selected from the group consisting of ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 3-ethyl-1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and mixtures thereof.
When a homopolymer is desired, it is most preferred to polymerize ethylene or propylene. When a copolymer is desired, the copolymer comprises monomer residues and one or more comonomer residues, each having from about 2 to about 20 carbon atoms per molecule. Suitable comonomers include, but are not limited to, aliphatic 1-olefins having from 3 to 20 carbon atoms per molecule, such as, for example, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, and other olefins and conjugated or nonconjugated diolefins such as 1,3-butadiene, isoprene, piperylene, 2,3-dimethyl-1,3-butadiene, 1,4-pentadiene, 1,7-hexadiene, and other such diolefins and mixtures thereof. When a copolymer is desired, it is preferred to polymerize ethylene and at least one comonomer selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 1-octene, and 1-decene. The amount of comonomer introduced into a reactor zone to produce a copolymer is generally from about 0.01 to about 10 weight percent comonomer based on the total weight of the monomer and comonomer, preferably, about 0.01 to about 5, and most preferably, 0.1 to 4. Alternatively, an amount sufficient to give the above described concentrations, by weight, in the copolymer produced can be used.
Processes that can polymerize at least one monomer to produce a polymer are known in the art, such as, for example, slurry polymerization, gas phase polymerization, and solution polymerization. It is preferred to perform a slurry polymerization in a loop reaction zone. Suitable diluents used in slurry polymerization are well known in the art and include hydrocarbons which are liquid under reaction conditions. The term xe2x80x9cdiluentxe2x80x9d as used in this disclosure does not necessarily mean an inert material; it is possible that a diluent can contribute to polymerization. Suitable hydrocarbons include, but are not limited to, cyclohexane, isobutane, n-butane, propane, n-pentane, isopentane, neopentane, and n-hexane. Furthermore, it is most preferred to use isobutane as the diluent in a slurry polymerization. Examples of such technology can be found in U.S. Pat. Nos. 4,424,341; 4,501,885; 4,613,484; 4,737,280; and 5,597,892; the entire disclosures of which are hereby incorporated by reference.
The catalyst compositions used in this process produce good quality polymer particles without substantially fouling the reactor. When the catalyst composition is to be used in a loop reactor zone under slurry polymerization conditions, it is preferred when the particle size of the solid oxide compound is in the range of about 10 to about 1000 micrometers, preferably about 25 to about 500 micrometers, and most preferably, 50 to 200 micrometers, for best control during polymerization.
In a more specific embodiment of this invention, a process is provided to produce a catalyst composition, the process comprising (optionally, xe2x80x9cconsisting essentially ofxe2x80x9d, or xe2x80x9cconsisting ofxe2x80x9d):
(1) calcining silica-alumina at a temperature in a range of about 300 to about 500xc2x0 C. for about 3 hours to produce a calcined silica-alumina;
(2) cooling the calcined silica-alumina and mixing 5 to 20% by weight of titanium tetrafluoride based on the weight of the calcined silica-alumina to produce a titanium tetrafluoride-containing silica-alumina; and
(3) calcining the titanium tetrafluoride-containing silica-alumina at a temperature in a range of about 300 to about 500xc2x0 C. for about 1 hour to produce a treated solid oxide compound; and
(4) contacting an organometal compound, an organoaluminum compound, and the treated solid oxide compound to produce the catalyst composition.
Hydrogen can be used with this invention in a polymerization process to control polymer molecular weight.
One of the features of this invention is that the TiF4, ZrF4, or treated solid oxide compound is itself an active catalyst for polymerization without the organometal compound, and it tends to produce very high molecular weight polymer relative to polymer produced by an organometal compound. Thus, when the TiF4, ZrF4, or the treated solid oxide compound is utilized with an organometal compound, it tends to produce bimodal polymers.
After the polymers are produced, they can be formed into various articles, such as, for example, household containers and utensils, film products, drums, fuel tanks, pipes, geomembranes, and liners. Various processes can form these articles. Usually, additives and modifiers are added to the polymer in order to provide desired effects. It is believed that by using the invention described herein, articles can be produced at a lower cost, while maintaining most, if not all, of the unique properties of polymers produced with metallocene catalysts.